November 25
The Former Spring Gate
Sun Position
The Sun is in Sagittarius near -21° declination. Northern Hemisphere nights are long; Southern Hemisphere is well into astronomical summer, with the Sun spending many hours above the horizon.
Sky Highlight
Aries is currently overhead from northern mid-latitudes in the early evening. Though the vernal equinox no longer lies in Aries (precession has moved it into Pisces, approaching Aquarius), the constellation still carries its historical weight as the first sign of the zodiac. In November its stars are well-placed for observation.
Deep Sky Object
NGC 772, spiral galaxy in Aries, about 130 million light-years away. An intermediate-brightness spiral with an unusually large, asymmetric outer arm, probably distorted by a small satellite galaxy. A compact target in modest telescopes, best from northern latitudes.
Featured Star
Hamal (α Arietis) is an orange giant 66 light-years away, spectral class K2IIICa-1, the brightest star in Aries and formerly one of the most important stars in the sky, because around 130 BCE it marked the position of the vernal equinox. Precession has since moved the equinox about 30° west, but the First Point of Aries is still named for the constellation, and Hamal still holds its place at the ram's forehead.
Around This Date
- November 25, 1915Albert Einstein presented his final formulation of the field equations of general relativity to the Prussian Academy of Sciences, completing a theory that would later predict black holes, gravitational waves, and the expanding universe.
- November 28, 1659Christiaan Huygens made his first detailed drawing of the Martian surface feature now called Syrtis Major, one of the earliest recorded observations of Martian surface detail.
Hamal once held the equinox and carried the weight of the year's beginning; precession moved the moment on, but the star is unmoved.